package ecnu.ecgbackend.utils;

import ecnu.ecgbackend.entity.User;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Data
@ConfigurationProperties(prefix = "jwt")
@Component
public class JwtUtils {
    private String secret;
    private Long expiration;
    private String generateToken(Map<String,Object> claims){
        Date expirationDate=new Date(System.currentTimeMillis()+expiration);
        return Jwts.builder().setClaims(claims).setExpiration(expirationDate).signWith(SignatureAlgorithm.HS512,secret).compact();
    }
    public Claims getClaimsFromToken(String token){
        Claims claims;
        try {
            claims=Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
        }catch (Exception e){
            claims=null;
        }
        return claims;
    }
    public String generateToken(UserDetails userDetails){
        Map<String,Object> claims=new HashMap<>(2);
        claims.put(Claims.SUBJECT,userDetails.getUsername());
        claims.put(Claims.ISSUED_AT,new Date());
        return generateToken(claims);
    }
    public String getUsernameFromToken(String token){
        String username;
        try{
            Claims claims=getClaimsFromToken(token);
            username=claims.getSubject();
        }catch (Exception e){
            username=null;
        }
        return username;
    }
    public Boolean isTokenExpired(String token){
        Claims claims=getClaimsFromToken(token);
        Date expiration=claims.getExpiration();
        return expiration.before(new Date());
    }
    public String refreshToken(String token){
        String refreshedToken;
        try{
            Claims claims=getClaimsFromToken(token);
            claims.put(Claims.ISSUED_AT,new Date());
            refreshedToken=generateToken(claims);
        }catch (Exception e){
            refreshedToken=null;
        }
        return refreshedToken;
    }
    public Boolean validateToken(String token,UserDetails userDetails){
        User user=(User) userDetails;
        String username=getUsernameFromToken(token);
        return (username.equals(user.getUsername())&&!isTokenExpired(token));
    }

}
